Homoleptic and heteroleptic ketodiiminate zinc complexes for the ROP of cyclic l-lactide

Homo- and heteroleptic ketodiiminate zinc complexes L12Zn2 (1, L1 = [Me2NC2H4NC(Me)CH]2CO), L2(ZnCp)2 (2, L2 = [Me2NC3H6NC(Me)CH]2CO, Cp = C5H5) and L2HZnCp* (3, Cp* = C5Me5) were synthesized and characterized by 1H and 13C NMR and IR spectroscopy as well as by elemental analysis and single crystal X-ray diffraction (sc-XRD, 2, 3). The catalytical activity of heteroleptic complexes 2 and 3 were tested in the ring-opening polymerization (ROP) of l-lactide. Homobimetallic complex 2 showed the highest activity and selectivity for the synthesis of cyclic polylactide (cPLLA; TOF = 17 460 h−1) at 100 °C in toluene solution, while linear polymers are formed with mononuclear complex 3.


Figure
Figure S7. 1 H NMR spectrum of the reaction of L 1 H2 with 2 eq. of ZnCp*2.

Figure
Figure S8. 1 H NMR spectrum of the reaction of L 1 H2 with 2 eq. of ZnCp2.

Figure S17 .
Figure S17.MWDs of cPLA obtained by reaction of L-LA and 2 and 3.

FinalFigure S17 .
Figure S17.MWDs of cPLA obtained by reaction of L-LA and 2 and 3.

Table S1
Crystal data for compound 2 and 3 III.Polymerization Studies

Table S1
Crystal data for compounds 2 and 3